jacobs chuck coming loose

Feb 01, 2008 12 Replies

Any tricks to helping keep my jacobs chuck from coming off the headstock?



When turning my bottle stoppers and finishing up the top/sanding (i.e. after pulling away the tailstock) the MT keeps slipping loose. This really sucks when it wobbles the piece into creating a catch.



I don't have this issue with drive spurs,etc but they almost always have the tailstock in place. Am I missing something or is this normal.



Use a drawbolt through the head stock to hold the chuck in place. See:

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you are missing a drawbar - add one and you will be much happier

Does your jacobs chuck MT arbor have a threaded hole in the tip for a draw bar? If so take it to HD or local hardware store and get a foot or so of matching allthread. If not or if there is a locking tang, it can likely be sawed off and the tip is probably soft enough for you to drill and tap for a piece of say 1/4 in. allthread long enough to go thru the headstock spindle and with an outboard washer & nut snug the arbor into the spindle taper. These draw bars are available commercially, but are easy to make. Darrell?

Turn to Safety, Arch Fortiter

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Ahh.. that explains it.

My ebay special has no threaded hole for a bolt.

Time to either upgrade (which wouldn't be bad as this one runs 10-20 thou out at least - but that may be a symptom, not the root problem) or modify this one.

Thanks guys.

A drawbar is certainly the most positive way of preventing the Morse taper from releasing. But you may be able to geet it to stay in by giving it a firm hit with a wooden mallet. (Make sure it's clean.)

you could send your assembly to anyone on this group who has machining capability to drill and dap a hole for you, or you can do it in a drill press and use a hand tap - the drawbar doesn't have to be centered, and it doesn't take a lot of force, you could use 3/16th diameter rod if 1/4 was too big, you could use piano wire too - you just need to keep a force on it to keep the taper seated. the Jacob's taper is a self holding taper, Morse taper is much less so, it is designed to release.

Common problem because you have more weight on the taper, and further from the headstock.. You could go to a Morse taper with a through bolt, but it's a lot easier to buy or make a bottle stopper chuck..

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mac

Please remove splinters before emailing

Mr Stubby will check in soon, but you can get a #2 almost anywhere suitable for mounting a 1/2" thread chuck. The "Golden Goose" brand, complete with pelican logo that I bought has a thread available for a drawbar of your own manufacture. Similar to

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Even bought a keyless - don't - the first time. Now resides on my sanding motor.

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